Copper corrosion by-product release in long-term stagnation experiments

• Published in: Water research (Oxford) 2002-03, Vol.36 (6), p.1547-1555
• Main Authors: Merkel, Till H., Groß, Hans-Jürgen, Werner, Wolfgang, Dahlke, Thomas, Reicherter, Susanne, Beuchle, Günter, Eberle, Siegfried H.
• Format: Article
• Language: English
• Subjects: Applied sciences; Buildings. Public works; By-product release; Copper - analysis; Copper - chemistry; Copper corrosion; Corrosion; Domestic installations; Drinking water; Drinking water and swimming-pool water. Desalination; Exact sciences and technology; Germany; Hydrogen-Ion Concentration; Kinetics; Microscopy, Electron; Oxidation-Reduction; Oxygen - chemistry; Piping; Pollution; Scale formation; Stagnation experiments; Water Pollution, Chemical - analysis; Water Supply - analysis; Water supply. Pipings. Water treatment; Water treatment and pollution
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/S0043-1354(01)00366-9

The effect of long-term stagnation on copper corrosion by-product release and corrosion rates was studied in pipe-rigs according to the German standard DIN 50931, Part 1. The analysis of the water phase was supplemented by surface analysis of corrosion scales. Copper concentration during stagnation did not follow a solubility process. The characteristic curves obtained can be explained by subsequent copper release and copper refixation processes. Oxygen consumption can be described by the first-order kinetic rate law. The corrosion scales consisted of cuprite (Cu2O) and malachite (CuCO3·Cu(OH)2). Malachite grew in well-defined crystals during stagnation, served as sink for dissolved copper and did not protect the pipe against corrosion attack. Copper concentrations measured after long-term stagnation (up to 122h) correspond to the solubility of malachite in the testwater.